Spray drying is a drying process in which raw liquid is atomized into fine droplets by an atomizer, and powdered products are obtained through direct contact between hot air (or other gas) and the droplets. The raw liquid materials can be solutions, emulsions, suspensions, as well as melts or pastes. According to application requirements, dried products can be produced in the form of powder, granules, hollow spheres or agglomerates.

 

The centrifugal spray dryer adopts hot air circulation, co-current feeding and centrifugal atomization drying principles. The drying air is filtered through primary and medium-efficiency air filters, heated by a heater, and then delivered to the air distributor at the top of the dryer. Hot air enters the drying chamber evenly in a spiral flow. Liquid materials are transported by a feed pump to the high-speed centrifugal atomizer mounted on the top of the tower body. Under the action of centrifugal force, the liquid is atomized into ultra-fine mist droplets, which come into co-current contact with hot air and are dried into finished products within an extremely short time. Final products are continuously collected from the bottom of the drying tower and cyclone separator. After dust removal treatment, the waste gas is discharged by the induced draft fan.

The centrifugal spray dryer primarily relies on the centrifugal force generated by a high‑speed rotating atomizer to disperse liquid materials into fine droplets. These droplets come into instant contact with hot air delivered through a volute hot air distributor for rapid drying.

 

The feed liquid is thrown out from the edge of the high‑speed rotating disk (linear speed above 110 m/s) under centrifugal force to achieve atomization. Given the relatively large atomized droplet size, the drying tower is designed with a larger diameter. Meanwhile, materials dispersed by centrifugal force feature uniformly sized droplets. Upon immediate contact with hot air, the droplets are dried into mostly hollow powder with consistent and fine particle size.

 

Centrifugal spray dryers are widely used in industrial sectors including chemical, food and pharmaceutical industries. Raw materials for spray drying vary greatly in properties, and finished products come with distinct technical requirements. Therefore, differences exist not only in technical processes, but also in process layout, equipment structure, operating conditions and auxiliary devices.

 

Multiple options are available for product separation and recovery systems, such as conventional and combined cyclone separators, bag filters, cyclone separator combined with bag filter, cyclone separator combined with wet dust collector, and bag filter combined with wet dust collector. Custom recovery solutions can be provided according to product characteristics and customer demands.

 

Based on different material properties and production requirements, post-processing systems can be optionally configured after spray drying, including secondary drying systems (e.g., ZLG vibrating fluidized bed or pneumatic conveying systems), dehumidification systems, batching systems and powder screening systems.

 

Drawing on advanced technologies from multiple sources and leveraging years of practical experience and technological innovation, Longxin Drying continuously optimizes centrifugal spray dryers and has obtained a number of patented technologies (e.g., ZL2021 2 2093525.2, ZL2023 2 1448173.0). Our equipment enjoys wide coverage in the domestic market and is exported overseas. During operation, customers have verified that key indicators of finished products, including moisture content, color, fragrance, particle size, solubility and specific gravity, all reach ideal performance.

 

(1) Rapid drying speed After atomization, the liquid material gains a greatly enlarged specific surface area. When contacting hot air, 95%–98% of moisture evaporates instantly within only a few seconds, making it especially suitable for drying heat‑sensitive materials.

 

(2) Excellent product performance and easy automatic operation Completed in a hot air environment, drying keeps the final products nearly spherical in shape similar to original droplets, delivering outstanding dispersibility, fluidity and solubility. The system runs stably with simple parameter adjustment and convenient control, enabling easy automatic production.

 

(3) Simplified production process & clean operation Liquids with a moisture content of 40%–60% (up to 90% for special materials) can be directly dried into powder or granules in a single step. No crushing or screening is required after drying, which simplifies procedures and improves product purity. The fully enclosed design effectively prevents dust emission and ensures a clean and hygienic working environment.

 

(4) Flexible product parameter adjustment Within a certain range, product indicators such as particle size, bulk density and moisture content can be flexibly adjusted by changing operating conditions, facilitating precise production control and management.

 

(5) Wide material adaptability A wide range of feed materials can be processed, including solutions, slurries, emulsions, suspensions, pastes, melts and even filter cakes.

(1) Chemical Products: Polyaluminum chloride, disperse dyes, reactive dyes, organic catalysts, fumed silica, washing powder, zinc sulfate, silicon dioxide, sodium metasilicate, potassium fluoride, calcium carbonate, potassium sulfate, inorganic catalysts, various waste liquids, etc.

  

(2) Food Industry: Whole milk powder, casein, cocoa milk powder, milk powder substitute, egg white / egg yolk powder; oatmeal, chicken extract, instant tea, seasoning spices, meat extract, protein, soybean protein, peanut protein, protein hydrolysate; corn steep liquor, corn starch, glucose, pectin, maltose, potassium sorbate, pumpkin powder and other food raw materials.

  

(3) Pharmaceuticals: Traditional Chinese medicine extract, medicinal gel, yeast, vitamins, antibiotics, amylase, lipase, etc.

  

(4) Plastics & Resins: AB and ABS emulsion, urea-formaldehyde resin, phenolic resin, melamine formaldehyde resin, polyethylene, polyvinyl chloride, etc.

  

(5) Detergents: High-grade washing powder, regular laundry powder, soap powder, soda powder, emulsifier, brightener, phosphate additives, etc.

   

(6) Ceramics: Alumina, zirconia, magnesium oxide, titanium oxide, magnesium titanate, clay, kaolin, various ferrites and metal oxides, etc.

 

  

  

Note: The water evaporation capacity is related to material properties, inlet hot air temperature and outlet temperature. The water evaporation curve at an outlet temperature of 90℃ is shown in the above figure (for model selection reference). Parameters are subject to change due to continuous product upgrading without prior notice.

  

  

  

(1) Name and physical properties of liquid materials: solid content (or moisture content), viscosity, surface tension, pH value, etc. (2) Product characteristics: bulk density of dried powder, allowable residual moisture content, particle size range, maximum allowable material temperature. (3) Special requirements (if any): specific gravity range, color, fragrance, etc. (4) Daily output and daily working hours. (5) Available energy sources: steam pressure, electric power, coal, fuel oil, natural gas, liquefied gas and other combustible fuels. (6) Control requirements: control mode of inlet & outlet air temperature, feeding system, air hammer and overall system control scheme. (7) Material collection requirements: select cyclone separator, bag filter, wet dust collector or combined solutions according to product features and environmental standards. (8) Other special requirements: workshop space, height limit, special power supply specifications and on-site conditions.

 

Remark: Customers may provide only part of the above information according to actual conditions. Other technical parameters and requirements can be confirmed through testing, experience evaluation and mutual negotiation.